When it is it appropriate to treat Strep throat?

Patient: I had strep throat for 4 days before being treated. I told the doctor that I have white spots and my throat was “on fire”. They did a rapid strep and it came negative, so he would not treat me. In the meantime, I exposed people to strep without knowing it. Once I found out, I took the antibiotics and within a couple of days took my son to the doctor as well. I told them that I had strep and I was concerned that he may have it as well. They did a rapid and that came negative. Three days later, they called to say that he has group b strep and needs an antibiotic. Why didn’t they treat me or him once they knew that I had symptoms and he was exposed (directly) to the illness?